Sergey Brin

2012 net
worth: $18.7 billion
2011 net
worth: $19.8 billionGoogle's
Sergey Brin saw his fortune drop by $1.1 billion in the past year thanks to a
3% dip in the search giant's stock. While cofounder Larry Page replaced Eric
Schmidt as CEO last year, Brin has been heading up special projects, reportedly
including a secretive hardware laboratory known as Google X. Another
initiative: Google Music.